Ryū, 流, or Ryūha, 流派, literally "style", is a body of knowledge, a tradition, or a school that has been transmitted for at least two generations. When referring to a martial arts schools, Ryuha, 流派, is the correct term and the suffix -ryu is added to the name of the school, as in Kukishin Ryu.
The term is Japanese in origin and is usually describes a traditional school of art or a specialized craftsmanship in various fields. For example there are Ryuha of Ikebana (生花, flower arrangement), of No (能) theater, of Japanese calligraphy Shodo (書道)and more. The most common use of this term is to describe a traditional martial arts school.